1. Field of the Invention
This invention relates to a design of a private branch exchange (PBX) using a computer network to route calls.
2. Description of Related Art
Private branch exchanges are expensive hardware equipment that most companies with more then very few employees typically buy and use. The cost can be several tens of thousands of dollars for a PBX with few lines. See a common design of an office computer and PBX system in FIG. 1. In some instances, systems including dedicated PBX server hardware have been used.
There are computer programs that enable long distance phone calls to be made over the Internet, at a very low or no cost apart from the cost of being connected to the Internet. Internet telephony standards are emerging. Equipment that connects a single phone line or multiple lines to a computer or a computer network is available and relatively inexpensive. The figures show Ethernet 10 interconnecting the Personal Computers (PCs), as Ethernet is very common network technology; but other types of networking are available. The Internet can be connected via a server 20 and firewall or can be directly connected to the network 10 interconnecting the PCs.
A typical PBX 30, along with associated hardware, performs at least the following functions: accept incoming calls and direct these calls to the intended recipient on an internal line; enable an internal line to connect to an outgoing line and make a call; enable an internal line to connect to another internal line and make a call; transfer outgoing calls or incoming calls from one internal line to another; add a line to existing call (conference calls); response with voice mail system when a line is busy or do not answers; allow calls to be held temporary without being connected, and later to be connected to a line upon request or when a line becomes available; service held calls with audio broadcast or announcements; record calls, and speed dial functions.